Economic conversion is a fancy way of saying that a country or business changes from making one thing to making something else.
Okay, let's say that a big factory is making a lot of cars. But suddenly, people stop wanting to buy cars and start wanting to buy bicycles. The factory can't just keep making cars because no one will buy them. Instead, they have to change what they're doing and start making bicycles.
This is called economic conversion because they're converting or changing what they're making to fit what people want to buy.
It's not just factories that can do this, countries can too. For example, let's say that a country used to make a lot of weapons but they don't want to anymore because they think it's better to make things that help people instead of hurting them. They might decide to switch to making things like medical supplies or solar panels.
Economic conversion is important because it allows countries and businesses to adapt to changing times and needs.